/* 公共的样式 */
* {
    /* 去掉浏览器内外边距 */
    margin: 0;   
    padding: 0;
    box-sizing: border-box;
}

html, body {
    height: 100%;
    background-image: url(../image/五子棋背景.jpg);
    background-repeat: no-repeat;
    /* 垂直水平居中 */
    background-position: center;
    /* 画面铺满 */
    background-size: cover;
}

/* 导航栏的美化 */
.nav {
    width: 100%;
    height: 50px;
    background-color: rgb(50, 50, 50);
    color: white;

    /* 上下居中，离左侧有20px距离 */
    display: flex;
    align-items: center;
    padding-left: 20px;
}

.container {
    height: calc(100% - 50px);
    width: 100%;

    display: flex;
    justify-content: center;
    align-items: center;
    background-color: rgba(255, 255, 255, 0);
}